diff --git a/rtiow/Cargo.lock b/rtiow/Cargo.lock
index ea6e3c7..3b6c875 100644
--- a/rtiow/Cargo.lock
+++ b/rtiow/Cargo.lock
@@ -458,18 +458,6 @@ dependencies = [
  "parking_lot 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "crossbeam-channel"
-version = "0.2.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "crossbeam-epoch 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "crossbeam-utils 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "smallvec 0.6.9 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "crossbeam-channel"
 version = "0.3.8"
@@ -511,19 +499,6 @@ dependencies = [
  "scopeguard 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "crossbeam-epoch"
-version = "0.6.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "arrayvec 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "crossbeam-utils 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "memoffset 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "scopeguard 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "crossbeam-epoch"
 version = "0.7.1"
@@ -545,11 +520,6 @@ dependencies = [
  "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "crossbeam-utils"
-version = "0.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
 [[package]]
 name = "crossbeam-utils"
 version = "0.6.5"
@@ -1269,15 +1239,6 @@ dependencies = [
  "stable_deref_trait 1.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "parking_lot"
-version = "0.6.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "lock_api 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "parking_lot_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "parking_lot"
 version = "0.7.1"
@@ -1287,18 +1248,6 @@ dependencies = [
  "parking_lot_core 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "parking_lot_core"
-version = "0.3.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "libc 0.2.49 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "smallvec 0.6.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "parking_lot_core"
 version = "0.4.0"
@@ -1665,7 +1614,7 @@ dependencies = [
  "chrono 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "cpuprofiler 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "criterion 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "crossbeam-channel 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "crossbeam-channel 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "getopts 0.2.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "image 0.19.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2525,15 +2474,12 @@ dependencies = [
 "checksum criterion 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)" = "1c6e5ee5b9652d4f851418c448af105642e1f99e9a2741a8ff45c0d2c911b1e0"
 "checksum criterion-plot 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4107e4a5abb94267e0149922b8ff49dc70a87cc202820fdbfc0d3e1edbdc4b16"
 "checksum crossbeam 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ad4c7ea749d9fb09e23c5cb17e3b70650860553a0e2744e38446b1803bf7db94"
-"checksum crossbeam-channel 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)" = "7b85741761b7f160bc5e7e0c14986ef685b7f8bf9b7ad081c60c604bb4649827"
 "checksum crossbeam-channel 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)" = "0f0ed1a4de2235cabda8558ff5840bffb97fcb64c97827f354a451307df5f72b"
 "checksum crossbeam-deque 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f739f8c5363aca78cfb059edf753d8f0d36908c348f3d8d1503f03d8b75d9cf3"
 "checksum crossbeam-deque 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)" = "05e44b8cf3e1a625844d1750e1f7820da46044ff6d28f4d43e455ba3e5bb2c13"
 "checksum crossbeam-epoch 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "927121f5407de9956180ff5e936fe3cf4324279280001cd56b669d28ee7e9150"
-"checksum crossbeam-epoch 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2449aaa4ec7ef96e5fb24db16024b935df718e9ae1cec0a1e68feeca2efca7b8"
 "checksum crossbeam-epoch 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)" = "04c9e3102cc2d69cd681412141b390abd55a362afc1540965dad0ad4d34280b4"
 "checksum crossbeam-utils 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "2760899e32a1d58d5abb31129f8fae5de75220bc2176e77ff7c627ae45c918d9"
-"checksum crossbeam-utils 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "677d453a17e8bd2b913fa38e8b9cf04bcdbb5be790aa294f2389661d72036015"
 "checksum crossbeam-utils 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)" = "f8306fcef4a7b563b76b7dd949ca48f52bc1141aa067d2ea09565f3e2652aa5c"
 "checksum csv 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)" = "9fd1c44c58078cfbeaf11fbb3eac9ae5534c23004ed770cc4bfb48e658ae4f04"
 "checksum csv-core 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "fa5cdef62f37e6ffe7d1f07a381bc0db32b7a3ff1cac0de56cb0d81e71f53d65"
@@ -2618,9 +2564,7 @@ dependencies = [
 "checksum openssl-probe 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "77af24da69f9d9341038eba93a073b1fdaaa1b788221b00a69bce9e762cb32de"
 "checksum openssl-sys 0.9.41 (registry+https://github.com/rust-lang/crates.io-index)" = "e4c77cdd67d31759b22aa72cfda3c65c12348f9e6c5420946b403c022fd0311a"
 "checksum owning_ref 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "49a4b8ea2179e6a2e27411d3bca09ca6dd630821cf6894c6c7c8467a8ee7ef13"
-"checksum parking_lot 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)" = "f0802bff09003b291ba756dc7e79313e51cc31667e94afbe847def490424cde5"
 "checksum parking_lot 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ab41b4aed082705d1056416ae4468b6ea99d52599ecf3169b00088d43113e337"
-"checksum parking_lot_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ad7f7e6ebdc79edff6fdcb87a55b620174f7a989e3eb31b65231f4af57f00b8c"
 "checksum parking_lot_core 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "94c8c7923936b28d546dfd14d4472eaf34c99b14e1c973a32b3e6d4eb04298c9"
 "checksum percent-encoding 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "31010dd2e1ac33d5b46a5b413495239882813e0369f8ed8a5e266f173602f831"
 "checksum phf 0.7.24 (registry+https://github.com/rust-lang/crates.io-index)" = "b3da44b85f8e8dfaec21adae67f95d93244b2ecf6ad2a692320598dcc8e6dd18"
diff --git a/rtiow/Cargo.toml b/rtiow/Cargo.toml
index 4b43c99..19372a0 100644
--- a/rtiow/Cargo.toml
+++ b/rtiow/Cargo.toml
@@ -13,7 +13,7 @@ actix-web = "0.7.8"
 askama = "0.7.1"
 chrono = "*"
 cpuprofiler = { version = "0.0.3", optional = true }
-crossbeam-channel = "0.2.4"
+crossbeam-channel = "0.3"
 getopts = "*"
 image = "0.19.0"
 lazy_static = "1.1.0"
diff --git a/rtiow/src/renderer.rs b/rtiow/src/renderer.rs
index 43d3e4f..ba26d43 100644
--- a/rtiow/src/renderer.rs
+++ b/rtiow/src/renderer.rs
@@ -282,7 +282,7 @@ pub fn render(scene: Scene, output_dir: &Path) -> std::result::Result<(), std::i
     let mut img = RgbImage::new(scene.width as u32, scene.height as u32);
     let total = scene.width * scene.height;
     let mut last_progress = 1000;
-    for (i, resp) in pixel_resp_rx.enumerate() {
+    for (i, resp) in pixel_resp_rx.iter().enumerate() {
         let y_inv = scene.height - resp.y - 1;
         img.put_pixel(
             resp.x as u32,